Vexing

I swallowed some blocks when I was that age.

Whoa bro, stop with the sexy talk. That kind of stuff ain't appropriate in the work place.

Education in some places

Oooohhhhh he's tryin'!

As a developer, you can only make plans, not instructions. Sometimes you plan out this really cool feature for your game to have, only to find out that its only possible to do it one particular way in the engine you are using and on top of that the only solution kills the framerate. At that point you have to either scrap the feature, figure out a way to have a revised feature (which requires more design man hours), or get your programmers to buckle down for an extra month or two to make it work.

Thats just one example though. Sometimes you have a newer piece of a game that interacts with an older piece that you forgot about and breaks both pieces. This can take anywhere from a day to months to fix depending on a bunch of factors. Many projects have failed because a bug in the foundation of the game wasnt found until later. A good example is the pc version of batman arkham knight.

Ive encountered some interesting blocks. Sometimes your team leads or even the investors get in the way by trying to control too much.

There are LOTS of things that can hold up a game. The best ways to avoid these blocks is to unfortunately play it safe. If you have a small scope (scope is the amount of work that needs to be done to have a shippable product) then you already know most of the bugs you will run into. If you take a lot of risks and do many things you havent done before then your scope gets too large and there are many more points in which the project can fail. Thats why you see a lot of similar games being released.